Fluid operated vise



Aug29, 1967 @NLUKAS 3,338,573

FLUID OPEHATED VISE Filed June l0, 1965 2 Sheets-Sheet 3 y 500 5v5 i4 M0 [9 506 70 V54@ 3,338,573 FLUID OPERATED VISE George N. Lukas, 4637 N. Clark St.,

Chicago, Ill. 60640 Filed June 1i), 1965, Ser. No. 462,889 14 Claims. (Cl. 269-23) This invention relates to a uid operated vise and more l particularly t-o a fluid operated vise which is particularly well adapted for mounting on the bed of a machine, such as, a milling machine for holding a work piece during a cutting operation.

Fluid operated vises which are particularly adapted for use in a machine, such as, a milling machine, generally present a problem in that the height yof the vise is rather high in order to provide .a vise which has a sufficient clamping force. Generally, these vises are used to hold one or more work pieces, and the tolerance with which a machine operator may be working may be within the ran-ge of one one-thousandth (0.001) of an inch. Thus, the vise which holds the work piece must not only secure the work piece rmly, but there can be no displacement of the vise jaw during a machining operation so that the' required tolerance may be maintained. It is true that most machines are provided with 1a clamp of some type for holding the work piece. However, it is found that the time which is utilized in placing the work piece into the clamp and taking it out, may be fairly substantial, so that it is particularly desirable to be able to place the work piece into position in a machine quickly and securely and to remove it quickly when desired. In order to achieve this end, fluid operated vises are often used. The fluid operated vises often have a severe disadvantage in that in order to achieve the necessary clamping force, the vise is large and `quite high as was mentioned above, so that there is an opportunity for bending or deformation of a vise jaw which results in a change in position of the work piece during a cutting operation. Furthermore, it is desirable to provide a fluid operated vise in which force is applied to more than one place on the jaw so that there is no opportunity for the jaw to become skewed during operation. It is, therefore, a principal object of the herein disclosed invention to provide a fluid operated vise which has a plurality of operating cylinders for applying a holding force to a plurality of places on the jaw to secure a uniform pressure across the jaw face in order to hold securely a work piece in a selected position.

It is another object of this invention to provide a fluid operated vise which has a plurality of cylinders and which cylinders are interconnected for transmittal of pressure between cylinders so that the force on the piston in each of the cylinders is equal.

It is a still further object of the instant invention to provide a liuid operated vise which has a plurality of pistons and has a means for limiting the excursion of the pistons which `means may be adjusted for a particular excursion of the pistons simply and conveniently.

It is a still further object of the present invention to provide an improved fluid operated vise construction in which an operating jaw may be simply and conveniently spaced relative to a fixed jaw to provide a vise having a wide range of positions for the vise jaws to accommodate work pieces f various sizes.

Other objects and uses of this invention will become readily apparent to those skilled in the art upon a perusal of the following specication in light of the accompanying drawings in which:

F-IGURE 1 is a cross-sectional elevational view taken through a uid operated vise embodying the herein dis- United States Patent O 31,338,573 Patented Aug. 29, 1,967

ICC

closed invention showing the interior construction of one of the cylinders of the vise;

FIGURE 2 is a cross sectional view taken on line 2-2 of FIGURE l, showing the relation of cylinders in a cylinder block;

FIGURE 3 is -a cross sectional view taken on line 3 3 of FIGURE 1;

FIGURE 4 is an enlarged fragmentary view of a portion of a piston skirt, an annular stop, a piston sleeve and a return spring shown in FIGURE l;

FIGURE 5 is a perspective view of a base which constitutes a portion of the fluid operated vise shown in FIGURE 1;

FIGURE 6 is a cross sectional view taken on line 6-6 of FIGURE 2 showing studs for securing the cylinder block to the base;

FIGURE 7 is an enlarged fragmentary view of a portion of .a threaded stud mounted in a portion of the base to secure the cylinder block to the base;

FIGURE 8 is a cross-sectional elevational view of a fluid operated vise embodying the present invention but with return springs mounted exterior of the cylinders; and

FIGURE 9 is a cross sectional view taken on line 9 9 of FIGURE 8.

Referring now to the drawings and especially to FIG- URES 1 and 2, a fluid operated vise embodying the herein disclosed invention is shown therein and is generally indicated by numeral 10. The vise 10 generally consists of a base 12, a cylinder block 14 secured to the base, and a pair of identical pistons 16 and 18 movably mounted in the cylinder block. A front plate 20 is connected to the pistons to secure the pistons to each other. A pair of stop rods 22. and 24 are connected to the pistons 16 and 18, respectively, and a back plate 26 is fixed to the stop Irods 22 and 24.

The cylinder block 14 has a pair of identical cylinders 28 and 30 formed therein which are interconnected so that fluid in both cylinders is under the same pressure. The cylinders 28 and 30 are parallel to each other and extend the length of the block to open on opposite ends of the block. Pistons 16 and 18 are sealingly and slideably mounted in the cylinder 28 and 30, respectively, and are positioned adjacent to one end of the cylinder block. The other end of each of the cylinders is sealed closed. Annular end closures 32 and 34 are mounted in one end of the cylinders 28 and 30, respectively. Each of the end closures has an O-ring 36 mounted internally for engagement with the respective stop rod to form a seal therewith, so that the stop rods are sealingly and slideably mounted in the respective end closures. An O-ring 37 is mounted on the exterior of each of the end closures to provide a seal between each end closure and the respective cylinder. Each of the end closures has a pair of apertures 38 extending therethrough, and pins 40 are positioned in the apertures of the end closures and registrable with apertures 39 in the cylinder block to lock the end closures into position. It should be noted that this particular construction does not require the use of screws to hold the end closures in position. The end closures are xed into position by simply drilling a pair of holes through each end closure and the respective portions of the cylinder block and driving pins into the apertures in the end closure and into the cylinder block thereby simplifying construction of the present invention.

As was mentioned above, the pistons 16 and 18 are identical in construction. The pistons 16 and 18 have head portions 42 and 44, respectively, which are adjacent to the front plate. Formed integral with the head portions 42 and 44 are piston skirts 46 and 48, respectively. The piston skirts 46 and 48 carry O-rings 50 3 and 52, respectively, to provide a seal between each piston and the respective cylinder.

Stop means is connected to the pistons through the piston skirts. Piston skirts 46 and 48 contain respective grooves 54 and 56 into which are mounted annular stops 58 and 60, respectively. Tubular piston sleeves 62 and 64 are slideably mounted in the piston skirts 46 and 48, respectively, and the piston sleeves are engageable with stops 58 and 60, respectively, so that the sleeves are locked into their respective pistons. The stop rods 22 and 24 have respective stop rod discs 66 and 68 formed integral with one end of the rods, and these stop rod discs 66 and 68 are engageable with the respective sleeves 62 and 64 so that the discs are relatively movable between the respective piston heads and the respective sleeves. Compression springs 70 and 72 are mounted within sleeves 62 and 64, respectively. The compression springs 70 and 72 each have one end in engagement with discs 66 and 68, respectively, and the other end in engagement with the annular stops 58 and 60, respectively, so that the heads of the pistons are constantly urged into engagement with the respective stop discs.

As was mentioned above, the stop rods are connected to the back plate 26. The back plate 26 has a pair of apertures 74 and 76 which receive stop rods 22 and 24, respectively. The back plate contains a pair of locking apertures '77 which locking register with apertures 79 in each of the stop rods 22 and 24, respectively, so that pins 78 and 80 are positioned through the back plate and the stop rods to lock the back plate to the stop rods. It may be appreciated that the connection between the stop rods and the back plate may be easily and conveniently made simply by drilling a hole through the back plate and stop rods and driving pins 78 and 80 into the aligned apertures.

To provide for adjustment of the stop means, the back plate has a threaded aperture 82 into which is mounted a stud 84. A lock nut 86 is mounted on stud 84 to hold the stud in a selected position. The stud 84 is engageable with the cylinder block so that the position of the back plate relative to the cylinder block may be selectively adjusted thereby. It is evident that the excursion of the pistons is limited by the cooperation of the lock plate or stud with the cylinder block and the connection of the stop rods with the respective pistons through the piston sleeves.

The pistons 16 and 18 have bosses 88 and 90, respectively, ormed on the faces which are spaced away from the back plate as may be seen in FIGURE 2. The front plate 20 has recesses 92 and 94 which mateably receive the bosses 88 and 90, respectively, so that the front plate is flush with the outer faces of the pistons 16 and 18. Screws 96 and 98 are mounted in the front plate and in pistons 16 and 18,-respectively, to secure the front plate to the pistons. The front plate has recessess 100 and 102 so that the front plate has a substantially flat surface on its outer most face since the heads of the screws are positioned in the recesses 100 and 102.

Looking now to FIGURE 2, it may be seen that the cylinder block has a plurality of bolt apertures 104 extending through the cylinder block between the cylinders. The bolt apertures are aligned in a straight line parallel to the cylinder.

The base 12 includes a at .support 106 with a jaw on stop S fixed thereon by a plurality of bolts 110. The support 106 has a plurality of identical apertures 112 in its central portion. These apertures are aligned in a straight line perpendicular to the face of the jaw 108. The spacing between the apertures 112 is less than the spacing between the apertures 104 in the cylinder block, but the distance between the apertures 104 and the distance between apertures 112 is a fractional amount, so that at least two of the apertures in each line may be aligned to receive a fastener. The apertures 112, as may be best seen in FIGURE 7, have a lower threaded portion 114 and an upper bearing portion 116. Two identical threaded studs 118 secure the cylinder block to the base. The threaded studs each have a head 120 which engages the cylinder block and a shank 122 which has its upper portion in engagement with cylinder block and lower portion in engagement with bearing portion 116 of a respective aperture 112. Each stud has a threaded portion 124 which threadedly mates with threaded aperture 114. Thus, tightening of the studs holds the cylinder block in frictional engagement with the base andthe stud bears against the base and the cylinder block to act as a pin so that there is no axial movement of the cylinder block relative to the base. Inasmuch as there are two studs, the opportunity for rotation is eliminated thereby rmly securing the cylinder block to the base.

The vise 10 is used in the following manner. First, the cylinder block 14 is positioned on the base 12 to an approximate desired position to receive a work piece between the front plate 20 and jaw 108. The cylinder block is secured to the mount 106 by two studs 118 in the manner described in detail above.

A work piece, which is not shown herein, is positional between the jaw and the front plate, and appropriate hydraulic fluid under pressure from a conventional source which is not shown is delivered to the vise. The cylinder block has a port 126 on one side thereof which is best shown in FIGURE 3 `and which is connected to the conventional source. The port communicates with a conduit 128 which has a leg 130 communicating with cylinder 30 and a leg 132 communicating with cylinder 28 to provide a manifold between the two cylinders. It is evident that the same pressure is applied to pistons 16 `and 18 since the cylinders are interconnected by the manifold. The pistons under pressure move axially and carry the front plate 20 toward the jaw until the front plate engages the work piece to hold the work piece between the jaw and the front plate. It should be noted that an appropriate jaw surface may be added to the front plate as is desired. Inasmuch as the pistons are both secured to the front plate, irrespective of where the work piece may be positioned relative to the pistons, there is no opportunity for the work piece to cause the front plate to cant thereby causing the pistons to bind in their respective cylinders.

In this manner, the pistons also serve as guides for each other to maintain the movement of the front plate as an axial movement relative to the cylinders. The movement of the pistons under pressure is against the force of the compression springs 70 and 72. When the pressure of the uid is relieved, the springs 70 and 72 which engage the annular stops 58 and 60, respectively, return the pistons into the cylinder until the front plate engages the cylinder block. The stop rods 22 and 24 thereby provide a base against which the springs operate in order to return the pistons.

It should be noted that the stop rods also perform a second function. These stop rods also prevent the pistons from being expelled from the respective cylinders in the event that the fluid under pressure is provided when there is no work piece between the front plate and the jaw. The pistons move outwardly until the piston sleeves 62 and 64 engage stop discs 66 and 68, respectively. The stop discs are connected to stop rods which are xed to the back plate 26, Thus, the cooperation of the back plate with the cylinder block limits the excursion of the pistons relative to the cylinder block. It should be noted that the instant vise may be used for a small pressing operation, and the excursion of the pistons may be adjusted by appropriately positioning the threaded stud 84. In order to position the stud 84, the lock nut 86 is loosened, and the stud is moved relative to the back plate until an appropriate excursion of the pistons is determined. The lock nut 86 is again tightened and the excursion of the pistons is then limited by engagement of the stud 84 with the cylinder block.

It may be seen that the vise 10 may be simply and ecO.`

nomically manufactured, and the maintenance and construction of the vise is held to -a minimum. The vise gives a very low silhouette, and during the clamp action between the jaw 108 and the front plate 20, the front plate has a minimum of opportunity to be deflected inasmuch as the pistons are spaced relative to each other to provide a pair of spaced forces applied to the front plate. The front plate is mounted on the pistons with a boss of each of the pistons in a respective recess of the front plate so that there is -a solid connection between the pistons and the front plate.

Looking now to FIGURES 8 and 9, a uid operated vise generally indicated by numeral 200 is shown therein, which vise is similar to vise 10, but has its return springs mounted exteriorly of the cylinders. The vise 200 generally includes a cylinder block 202 which is similar to cylinder bloc 14 and is also adapted for mounting on the base 12 described in detail above. Vise 200 generally includes a pair of identical pistons 204 and 206 which are sealingly and slideably mounted in the cylinder block. The pistons are connected to a front plate 203 on one side, and the other side of pistons 204 and 206 are connected to stop rods 210 and 212, respectively. The stop rods are connected to a back plate 214 which has a threaded limiting stud 216 mounted therein and engageable with the cylinder block.

The cylinder block has a pair of identical and parallel cylinders 218 and 220 in which are sealingly and slideably mounted pistons 204 and 206, respectively. O-rings 222 and 224 are mounted on the outer periphery of the pistons 204 and 206, respectively, and the O-rings are positioned in sealing engagement with their respective cylinders 218 and 220. The pistons 204 and 206 have respective bosses 226 and 228 formed integral with one face, and the front plate has recesses 230 and 232 mateably receiving bosses 226 and 228, respectively. Screws 234 and 236 secure the pistons 204 and 206, respectively, to the'v front plate 208. The front plate has screw head recesses 236 and 238 for the same purpose that the front plate 20 has recesses 100 and 102.

An end closure 240 is positioned in the end of cylinder 218 spaced away from the front plate, and an identical end closure 242 is positioned in the like end of cylinder 220. The end closures being identical in construction, each have an outer O-ring 244 in engagement with the cylinder to seal closed that end of the cylinder. A plurality of screws 246 secure the end closures to the cylinder block. End closures 240 and 242 contain spring recesses 248 and 250 for reasons which will become apparent hereinafter.

As was mentioned above, the stop rods 210 and 212 are xed to pistons 204 and 206, respectively. The stop rods 210 and 212 extend through the end closures 240 and 242, respectively, and O-rings 252 mounted internally of each of the end closures engage the respective stop rods to provide a seal between each end closure and the re-` spective stop rod. The stop rods 210 and 212 have reduced threaded portions 254 and 256, respectively, on the end opposite the end connected to the respective piston. The back plate 212 has a pair of apertures 25S and 260 which receive the respective threaded portions 254 and 256. Nuts 262 and 264 are mounted on the threaded portions 254 and 256, respectively, to connect the rods to the back plate 214. Compression springs 265 are positioned with one end in each of the spring recesses 248 and 250 and the other end in engagement with the back plate, The back plate 214 also has a threaded aperture 266 which threadably receives the stop limit stud 216. A lock nut 268 is mounted on the stop limit stud to lock the stud relative to the back plate. i

The cylinder block includes a manifold 270 which provides a means of communication between the cylinders 218 and 220 to equalize the pressure in the two cylinders and a means for entrance of the fluid under pressure to the cylinder body. The cylinder block also has in its central portion `a plurality of apertures 272 which have each of their respective axes perpendicular to a plane dened by the axes of -the cylinders and which apertures are in a line which is parallel to the axes of the cylinders. The apertures 272 are spaced identically to the apertures 104 and they are adapted to receive the studs 118 in the manner described in detail above.

Vise 200 operates in a manner quite similar to the above described vise 10. Cylinder block 202 is mounted on base 12 in the same manner that cylinder block 14 is mounted on the same base. Hydraulic uid under pressure is delivered to the cylinders 218 and 220 through manifold 270 from a conventional source which is also not shown, so that the pistons 204 and 206 are forced outward carrying with them front plate 208. In the event that a work piece is positioned between the front plate and the jaw, the work piece is held therebetween. When the hydraulic pressure is relieved, the compression of the springs 265 urges the back plate 214 away from the cylinder block to retract the pistons 204 and 206 until front plate engages cylinder block.

It may be appreciated that in the event that there should be no work piece between the front plate and the jaw, or should the device be used as a small press, the

stud 216 then acts as means for limiting excursion of the pistons out lof the cylinder block. The amount of excursion is limited by the appropriate position of limit stud 216.

It is evident that the vise 200 is also simple Iand economical to manufacture and has many of the same advantages that are attributed to vise 10. The construction of vise 200 is superior to vise 10 in that there may be a greater adjustment of the means for limiting the excursion of the pistons relative to the cylinder blo-ck; however, it does suffer the disadvantage of having a greater overall length than the other vise.

Although a specific embodiment of the herein disclosed invention has been shown and described in detail above, it is readily apparent that those skilled in the art may make various changes and modifications in the subject invention without departing from the spirit and scope Ithereof. It is to be expressly understood that the instant invention is limited only by the appended claims.

What is claimed is:

1. In a fluid operated vise, the combination comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connected to the cylinders vfor equalizing the pressure between said cylinders, a

piston sealingly and slideably mounted in each of said cylinders, each of said pistons having an elongated piston skirt formed integral therewith, a piston sleeve slideably mounted within each of said piston skirts, means for limiting the -movement of the piston sleeve relative to the piston skirt in one direction to retain the piston sleeve within the piston, a stop rod having one end engageable with the piston sleeve, a back plate fixed to said stop rods, a spring connected to the piston and to the stop rod for retracting the piston, and a front plate iixed to the pistons to secure the pistons to each other, whereby fluid under pressure delivered to the cylinder extends the pistons from their respective cylinders simultaneously at the same rate and the pistons are limited in their axial movement by cooperation of the piston sleeve with the stop rod.

2. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connected to the cylinders for equalizing pressure between both cylinders, a piston sealingly and slideably mounted in each of said cylinders, an end closure sealingly mounted in one end of each of said cylinders for sealing closed that end of the respective cylinder, a back plate connected to the pistons for limiting axial displacement of the pistons in one direction, a front plate fixed to the pistons to secure the pistons to each other, and means for returning the pistons.

3. In a fluid operated vise, the combination, com- 7 prising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders to equalize the pressure between both cylinders, a piston sealingly and slideably mounted in each of said cylinders, an end closure sealingly mounted in one end of each of said cylinders for closing that end of said cylinders, a back plate Connected to the pistons for limiting axial displacement of the pistons in one direction, each of said pistons having a boss formed integral with one end, a front plate having a pair of apertures mateably receiving the boss of each of said pistons and being secured thereto, and spring means for returning the pistons.

4. In a fluid operated vise, the combination, comprising a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders for equalizing the pressure between the cylinders, a piston sealingly and slideably mounted in each of the cylinders, an end closure mounted in one end of each of the cylinders to seal closed that end of the respective cylinder, a stop rod fixed to each of the pistons and being sealingly and slideably mounted in the respective end closure, a back plate connected to the stop rods, a front plate connecting the pistons, spring means for lretracting the pistons into the respective cylinder after being extended by a fluid pressure, and limit means connected to the back plate limiting the excursion of the pistons.

5. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders for-med therein, a manifold connecting the cylinders for equalizing the pressure between the cylinders, a piston sealingly and slideably mounted in each of said cylinders, means closing one end of each of said cylinders, a back plate -connected to the pistons for limiting axial displacement of the pistons in one direction, each of said pistons having a 'boss formed integral with the end spaced from the back plate, a front plate having a pair of apertures mating with the boss of each of said pistons and being secured thereto, spring means for returning the piston after being axially displaced by iiuid pressure to place the front plate in engagement with the cylinder block, a base connected to the cylinder block, and a stop fixed to said base and cooperative with the front plate for holding a work piece therebetween.

6. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders, a manifold connecting the cylinders for equalizing the pressure between the cylinders, a lpiston sealingly and slideably mounted in each of the cylinders, an end closure sealingly mounted in one end of each of the cylinders for sealing closed that end of the cylinder, a stop rod connected to each of the pistons and being sealingly and slideably mounted in its respective end closure, a back plate connected to the stop rods, a spring engaging each of the end closures and the back plate for retracting the pistons extended by a Huid pressure, adjustable limit means connected to the back plate for limiting the excursion of the pistons, and a front plate connected to the pistons to limit retraction of the pistons into the respective cylinder.

7. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders, a manifold connecting the cylinders for equalizing the pressure between said cylinders, a piston sealingly and slideably mounted in each of said cylinders, an end closure sealingly mounted in one end of each of the cylinders for sealing closed that end of the respective cylinder, a stop rod having one end fixed to one face of each of the pistons and being sealingly and slideably mounted in the respective end closure, a back plate connected to the opposite ends of the stop rods, a compression spring surrounding a portion of each of the stop rods and positioned in engagement with the respective end closure and the back plate to urge constantly the respective piston toward the respective end closure, a stud threadedly Imounted in the back plate and engageable with the cylinder block to limit the excursion of the pistons by iiuid pressure, each of said pistons having a concentric boss portion formed on the face opposite the face connected to the stop rod, and a front plate having a pair of recesses mateably receiving the bosses of the respective pistons and being secured thereto.

8. In a uid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders, a manifold connecting the cylinders for equalizing pressure in the cylinder, a piston sealingly and slideably mounted in each of said cylinders, an end closure sealingly mounted in one end of each of said cylinders for sealing closed that end of the respective cylinder, a stop rod connected to each of the cylinders and being sealingly and slideably mounted in the respective end closure, a back Iplate connecting the stop rods, a compression spring mounted between such of the end closures and the back plate to urge constantly the pistons toward their respective end closures, a front plate connected to the pistons, said cylinder block having a plurality of apertures extending perpendicular to the axis of the cylinder and said apertures being aligned in a line -parallel to the axes of the cylinders, a base having a plurality of threaded apertures having their axes parallel and in a single plane, said apertures in the base having a distance between adjacent apertures different than the distance between adjacent apertures in the cylinder block, a threaded stud removably mounted in one of the apertures of the cylin- -der block and threadedly mounted in one of the apertures of the base, a seco-nd threaded stud removably mounted in another of the apertures of the cylinder block and being threadedly mounted in a second aperture of the base, and a stop being `fixed to the base and cooperative with the front plate for holding a work piece therebetween.

9. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connected to the cylinders for equalizing the pressure between the cylinders, a piston sealingly and slideably mounted in each of said cylinders, an end closure mounted in one end of each of said cylinders for sealing lclosed that end of the respective cylinder, a back plate -connected to the pistons for limiting axial displacement of the pistons in one direction, a front plate xed to the pistons to secure the pistons to each other and engageable with the cylinder block to limit `retraction of the pistons into the cylinder block, spring means for returning the pistons to place the front plate in engagement with the cylinder block, a base connected to the cylinder block, and a stop fixed to said base and cooperatvie with the front plate for holding a work piece therebetween.

10. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders for equalizing the pressure between said cylinders,

a piston sealingly and slideably mounted in each of sai-d cylinders, an end closure sealingly mounted in one end of each of said cylinders for sealing closed said one end of the respective cylinder, a back plate connected to the pistons for limiting axial ldisplacement of the pistons in one direction, a front plate lixed to the pistons to secure the pistons to each other, spring means 'for returning the pistons, a base connected to the cylinder block, said -cylinder block having a plurality of bolt apertures extending in an attitude perpendicular to the axes of the cylinders and said apertures being aligned in a line parallel to the axes of the cylinders, said base having a plurality of threaded apertures spaced from each other a shorter distance than the spacing between adjacent apertures in the cylinder block, a threaded stud removably mounted in one of the apertures in the cylinder block and threadedly mounted in one of the apertures of the base, and a jaw Xed to said base and being substantially perpendicular to the axis of the cylinder and cooperative with the front plate for holding a work piece therebetween.

11. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders for equalizing pressure between the cylinders, a piston sealingly and slide-ably mounted in each of said cylinders, an end closure sealingly mounted in one end of each of said cylinders for sealing closed that end of the respective cylinder, a back plate connected to the pistons for limiting axial displacement of the pistons in one direction, each of said pistons having a boss formed integral with one end, a front plate having a pair of apertures mateably receiving the bosses of the pistons and being secured thereto and being engageable with the cylinder block to limit retraction of the pistons into the cylinder block, spring means for returning the pistons, a threaded stud mounted in the back plate and engageable with the cylinder block to regulate the axial displacement of the pistons, said cylinder block having a plurality of elongated apertures extending therethrough being aligned in a line parallel to the axis of the cylinder, a base having a plurality of threaded apertures aligned in a straight line and having a space between said apertures less than the apertures in the cylinder block, a stop xed to said base and having a face substantially perpendicular to the line of said threaded apertures of the base, a stud mounted in one of the apertures of the cylinder block and threadedly mounted in one of the apertures of the base to secure the cylinder block to the base, Aand means for aligning the lines of the apertures in the cylinder block and in the base to align the front plate substantially parallel to the face of the stop for holding a work piece between the base and the front plate.

12. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders for equalizing pressure between the cylinders, a piston sealingly and slideably mounted in each of the cylinders, an end closure sealingly mounted at one end of each of said cylinders for sealing that end of the respective cylinder, each of said pistons having a piston skirt formed integral therewith, a piston sleeve slideably mounted within each of the piston skirts, means for limiting movement of the piston sleeve in one ,direction to lock the piston sleeve into the piston, -a stop rod slideably and sealingly mounted in each of the end closures and being engageable with the piston sleeve for limiting movement of the respective piston, a back plate connected to the stop rods for limiting the axial displacement of the stop rods in one direction, a spring connected to each of the stop rods and its respective piston for retracting the piston, and a front plate fixed to the pistons to secure the pistons to each other, whereby fluid under pressure delivered to the cylinder extends the pistons outward to move the f-ront plate and the movement of the pistons is limited by the engagement of the piston sleeve with the stop rod and the engagement of the back plate with the cylinder block.

13. In a fluid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders for equalizing uid pressure between the cylinder, a piston sealingly and slideably mounted in each of the cylinders, each of said pistons having an elongated skirt formed integral therewith, a piston sleeve movably mounted within the piston skirt, means for holding the piston sleeve within the piston skirt, an end closure sealingly mounted in one end of each of said cylinders for sealing closed that end of the respective cylinder, a stop rod slideably and sealingly mounted in each end closure and having one end engageable with the piston sleeve for limiting axial movement of the piston, a spring connected to each stop rod and the respective piston skirt to re-l tract the respective piston, a back plate connected to the stop Irods to limit movement of the stop `rods in one direction, a front plate fixed to the pistons to secure the pistons to each other and being engageable with the cylinder to limit retraction of the pistons into the cylinder block, said cylinder block having a plurality of parallel spaced apertures perpendicular to a plate determined `by axes of the cylinders and aligned in a straight line, a base having a plurality of threaded apertures aligned in Ia straight line and being spaced from adjacent apertures to have at least two `apertures in registry with two apermovably mounted within the piston skirt, an annular stop fixed to said base and said stop having a face perpendicular to the line of the threaded apertures of said base, and a plurality of threaded studs mounted in a portion of the apertures of the cylinder block and threadedly mounted in selected apertures of the base to secure the cylinder block to the base.

14. In a liuid operated vise, the combination, comprising, a cylinder block having a pair of identical parallel cylinders formed therein, a manifold connecting the cylinders for equalizing the pressure between both cylinders, a piston sealingly and slideably mounted in each of said cylinders, e-ach of said pistons having an elongated skirt formed integral therewith, a piston sleeve movably monuted within the piston skirt, an annular stop connected to each of the piston skirts and engageable with the respective piston sleeve to hold the piston sleeve within the respective piston skirt, an enlarged disc movably mounted Within the piston skirt and engageable with the piston sleeve to `be limited in motion between the piston and the piston sleeve, an end closure sealingly mounted in one end of each of said cylinders adjacent to the respective piston skirt for sealing closed one end of the respective cylinder, a stop rod fixed to each of the discs and being slideably and sealingly mounted in the respective end closure, a compression spring extending between each of the discs and the respective annular stop to urge constantly the piston into engagement with the disc, a back plate connected to the stop rods to limit movement of the stop rods in one direction, each of said pistons having a concentric boss on the side spaced from the back plate, and a front plate having a pair of recesses mateably receiving the bosses of the pistons and being secured to the pistons to secure the pistons to each other and being engageable with the cylinder block to limit retraction of the pistons into the cylinder block by the action of the springs.

References Cited UNITED STATES PATENTS 1,782,595 ll/l930 Amsler 92-146 X 2,987,972 6/1961 Schneider 269-34 ROBERT C. RIORDON, Primary Examiner. JAMES F, MCKEOWN, Assistant Examiner.

UNITED STATES PATENT oEEICE CERTIFICATE 0F CORRECTION Patent No. 3 ,338 ,573 August 29 1967 George N. Lukas It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 43, for "Cylinder" read Cylinders line 57, for "regstrable" read registerable column 3, l 65 for "on" read or column 5 line 17 for "bloc" read blockc column 8 line 5l for "oooperatvie" read cooperative column 9, line 63, for "cylinder" read cylind ers column l0, line l4, after "der" insert block line 16, for "plate" read plane line 2l, for "movably mounted within the piston skirt, an annular" read tures in the cylinder block in related positions, a same column l0, line 35 for "monuted" read mounted Signed and sealed this 15th day of October 1968 (SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

2. IN A FLUID OPERATED VISE, THE COMBINATION, COMPRISING, A CYLINDER BLOCK HAVING A PAIR OF IDENTICAL PARALLEL CYLINDERS FORMED THEREIN, A MANIFOLD CONNECTED TO THE CYLINDERS FOR EQUALIZING PRESSURE BETWEEN BOTH CYLINDERS, A PISTON SEALINGLY AND SLIDEABLY MOUNTED IN EACH OF SAID CYLINDERS, AN END CLOSURE SEALINGLY MOUNTED IN ONE END OF EACH OF SAID CYLINDERS FOR SEALING CLOSED THAT END OF THE RESPECTIVE CYLINDER, A BACK PLATE CONNECTED TO THE PISTONS FOR LIMITING AXIAL DISPLACEMENT OF THE PISTONS IN ONE DIRECTION, A FRONT PLATE FIXED TO THE PISTONS TO SECURE THE PISTONS TO EACH OTHER, AND MEANS FOR RETURNING THE PISTONS. 